Oxygen probes which are essentially galvanic cells and which are adapted to measure the oxygen content in a molten metal are well known. However, all the prior art oxygen probes have suffered from one drawback which remains as a problem, namely the ability of the probe components to maintain the required electrical contact between the solid electrolyte and its electrode throughout a reasonable lifetime. As a result, the lifetime of prior art probes was much less than desired.
In order to overcome the difficulties encountered with prior art oxygen probes, the probe shown in U.S. Pat. No. 3,772,177 developed. The probe shown in this patent provides increased contact pressure between the solid electrolyte and the reference electrode by utilizing the thermal expansive properties of the contact rod.
While the probe disclosed in U.S. Pat. No. 3,772,177 operates satisfactorily, in many respects, for intended purpose, a more reliable rugged probe structure with increased lifetime is desired.